SEATTLE — The Jets’ offense was, for the first and only time Sunday, rumbling down the field. It was early in the second quarter, before the rain and the misery and the dejection, and the end zone loomed 6 yards away. Mark Sanchez pumped once. He faked. Looking right, Sanchez cocked his arm and threw.

That the ball fluttered and wobbled toward Dustin Keller was an appropriate metaphor for the Jets’ desultory and disappointing season. That the ball was snatched out of the air by Seattle cornerback Richard Sherman, who baited Sanchez into the poor throw and worse decision, was just as fitting, and, perhaps, as decisive.

The Jets never threatened after that interception, and after a 28-7 loss in the deafening din of CenturyLink Field that dropped their record to 3-6, it is reasonable to ask when they will again. Next week in St. Louis? On Thanksgiving against New England? In the season finale at Buffalo? Will that game even matter, or will it be the last in a season long decided, the Jets’ obituary already written on a cold, misty day in the Pacific Northwest?

When it was over, cheerleaders danced, fans whooped and Seahawks shimmied — the sights and sounds of a team ascending. A singalong coursed through the crowd, and to the Jets it must have sounded like a dirge. Coach Rex Ryan’s voice quavered during his postgame news conference. Players spoke softly, ruefully, regretfully.

“If this loss don’t affect anybody, they have no heart,” said linebacker Bryan Thomas, who added an expletive for emphasis.

The Jets might have heart. No one is questioning that. But what they do not have is a productive offense, a consistent defense or a special-teams unit that can counteract lapses in other phases. The Jets amassed 185 yards and went 2 for 11 on third down. They committed three turnovers and six penalties. They missed loads of tackles and scored their only touchdown on defense, a 21-yard fumble return by Muhammad Wilkerson, who headlined a group that performed admirably until the fourth quarter.

On his 26th birthday — and playing against his former coach at Southern California, Pete Carroll, who disagreed with Sanchez’s decision to leave college a year early — Sanchez endured what might have been his worst game of the season, completing 9 of 22 passes for 124 yards and an interception, his fourth in the red zone, while also losing a fumble. It only may have been his worst game, because there are two others — San Francisco, Miami — in contention.

The Jets for so long have championed Sanchez, and despite the latest installment of his struggles, they do not appear inclined to consider a change, elevating Tim Tebow.

“Again, I know this is a common theme, but if it was on one guy, it’s easy to fix; it’s much more,” Ryan said, adding: “We’re sticking with Mark. We know he has to get better. And everybody around him has to get better.”

Photo

The Seahawks’ Sidney Rice making one of his two fourth-quarter touchdown catches Sunday. The Jets, who fell to 3-6, were outgained by Seattle, 363-185.Credit
Otto Greule Jr/Getty Images

But how? Before the Jets’ game against Miami two weeks ago, Ryan raved about the quality of their practices. Then they lost by 21 points. Before Sunday, Ryan again lauded his players’ work ethic and attention to detail. Then they lost by 21 points.

The margin of defeat is not the only distressing pattern. In a stadium where the Seahawks rarely lose, the Jets never win. As it happened in 2008, the last time they visited Seattle, the Jets lost Sunday for the third time in four games, for the sixth time this season. One big difference: that loss four years was on Dec. 21.

In their last 12 games, the Jets are 3-9, with Sanchez starting all of them. No matter how stubbornly they cling to the notion that a playoff berth is possible, history suggests otherwise: since the 1970 merger, only four teams that started 3-6 or worse have made the playoffs, according to the Elias Sports Bureau, and none since the 1996 Jacksonville Jaguars.

“I don’t know how many more losses you want to spot somebody before you think you can make the playoffs,” Ryan said.

Three weeks ago, Sanchez played Tom Brady to a standstill in a loss to New England. But over the last two games, he has been embarrassed by, first, a backup, in Miami’s Matt Moore. And now a rookie, Russell Wilson, who, despite being sacked four times and fumbling twice, still completed 12 of 19 passes for 188 yards and two long touchdowns, a 38-yarder to Golden Tate in the first quarter and a 31-yarder to Sidney Rice with 13 minutes 33 seconds remaining.

That score extended the Seahawks’ lead to 21-7, and on the next possession, Sanchez was sacked and fumbled. Seattle converted the turnover into a touchdown, with Tate firing a 23-yard pass to Rice. It was 28-7, and it was all over for the Jets.

“We can’t win with the way I played today,” Sanchez said.

At the beginning of the week, back when Ryan said the Jets were not “sniffing” the playoffs, he showed his players the A.F.C. standings, bunched tighter than an old turtleneck. He preached the power of possibility.

However humbled the Jets were by Miami, the loss did not humble them. Rather, it produced the loudest 3-5 team in the league, with Antonio Cromartie telling NFL Network that the Jets were “definitely” making the playoffs. Afterward, with the Jets languishing in 11th place in the 16-team conference, Cromartie said he was just as confident, and he told Sanchez skeptics to smooch one of his body parts if they preferred a new quarterback.

Embracing adversity is a team specialty. Then again, so is peddling positives. It was a quixotic idea the Jets had, expecting that the shortcomings they addressed during the bye week would be miraculously resolved by Sunday. As if all of a sudden Sanchez would stop committing turnovers in the red zone and the special teams would stop undermining their cause.

Before the interception, the Jets had the ball at the Seattle 1. A false-start penalty on Keller — one of three on the team — pushed them back 5 yards and took the ball out of the hands of Tebow, who, it appeared, was going to score his first touchdown as a Jet. Then a fumbled punt by Jeremy Kerley led to a 1-yard touchdown by Marshawn Lynch, putting Seattle ahead by 14-7, a seemingly insurmountable margin.

“There’s not much else to say,” Chaz Schilens said. “It’s not good.”

A version of this article appears in print on November 12, 2012, on page D3 of the New York edition with the headline: Gloom Engulfs Jets as Playoff Hopes Fade in the Seattle Mist. Order Reprints|Today's Paper|Subscribe